The present invention relates to the chain arts, and in particular, a short pitch tooth chain that provides improved noise reduction over conventional tooth chains.
Drive chain systems and timing chain systems incorporating known chains such as inverted tooth chains and roller chains have several components of undesirable noise. A major source of noise is the sound generated as the chain engaging members, such as inverted teeth or rollers, leave the span and collide with a sprocket during meshing. The resulting impact noise is repeated with a frequency generally equal to that of the frequency of the chain meshing with the sprocket. It is known that the impact noise levels associated with chains can be reduced by altering the engagement geometry of the chain and/or sprocket to, in part, reduce the impact energy that must be absorbed during the meshing process.
The present invention contemplates a new and improved short pitch tooth chain which provides improved noise reduction over conventional inverted tooth chains.
In accordance with one aspect of the present invention, a tooth chain is disclosed. The tooth chain includes a first link having a first aperture spaced from a second aperture by a first distance; a second link having a first toe spaced from a second toe by a second distance, the second link having a third aperture and being connected to the first link by a first pin extending through the first and third apertures; a third link having a third toe spaced from a fourth toe by the second distance, the third link having a fourth aperture and being connected to the first link by a second pin extending through the second and fourth apertures; and the first distance defining a chain pitch and the second distance defining a sprocket chordal pitch wherein the chain pitch is about twice the sprocket chordal pitch.
In accordance with another aspect of the present invention, a chain system is disclosed. The chain system includes a first sprocket having a first plurality of sprocket teeth spaced apart by a first distance; a second sprocket having a second plurality of sprocket teeth spaced apart by the first distance; a chain wrapped around the first and second sprockets, the chain including a first link having a first aperture spaced from a second aperture by a second distance, a second link having a first toe spaced from a second toe by the first distance, the second link having a third aperture and being connected to the first link by a first pin extending through the first and third apertures, a third link having a third toe spaced from a fourth toe by the first distance, the third link having a fourth aperture and being connected to the first link by a second pin extending through the second and fourth apertures; and the first distance defining a sprocket chordal pitch and the second distance defining a chain pitch wherein the chain pitch is about twice the sprocket chordal pitch.
In accordance with a further aspect of the present invention, a chain is disclosed. The chain includes a first link member having a first aperture spaced from a second aperture by a first distance; a second link member connected to the first link member and having a first toe spaced from a second toe by a second distance, the toes being adapted for engagement with tooth spaces associated with a sprocket, the tooth spaces being spaced apart by a third distance; and the second distance being substantially equal to the third distance, and the second distance being about one half of the first distance.
In accordance with yet another aspect of the present invention, a chain system is disclosed. The chain system includes a first sprocket having a first plurality of tooth spaces spaced apart by a first distance; a second sprocket having a second plurality of tooth spaces spaced apart by the first distance; and a chain including a first link member having a first aperture spaced from a second aperture by a second distance, a second link member connected to the first link member and having a first toe spaced from a second toe by a third distance, the toes being adapted for engagement with the first and second plurality of tooth spaces, and the first distance being substantially equal to the third distance, and the third distance being about one half of the second distance.
In accordance with a still further aspect of the present invention, a link member for a chain is disclosed. The link member includes a body portion defining a first toe and a second toe spaced from the first toe by a predetermined distance, the toes adapted for meshing engagement with tooth spaces associated with a sprocket, and the link member further comprising a single aperture extending through the body portion.
One advantage of the present invention is the provision of a short pitch tooth chain which reduces noise levels by increasing the frequency at which the chain meshes with a sprocket to a level which is inaudible, or at least less audible to the human ear.
Another advantage of the present invention is the provision of a short pitch tooth chain having a chain pitch value which is approximately twice a sprocket chordal pitch value.
A further advantage of the present invention is the provision of a chain system having a short pitch tooth chain that reduces noise levels by increasing the frequency at which the chain meshes with a sprocket to a level which is inaudible, or at least less audible to the human ear.
Yet another advantage of the present invention is the provision of chain system having a short pitch tooth chain with a chain pitch value which is approximately twice a sprocket chordal pitch value.
Still further objects and advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments.